1. Field of the Invention
The present invention relates to a surface mounting device and the method thereof capable of simultaneous process on a plurality of printed circuit boards, and more particularly, to a surface mounting device and the method thereof capable of simultaneously picking and placing electronic parts on a plurality of printed circuit boards using a transfer and a conveyer that are movable.
2. Description of the Related Art
Generally, a surface mounting device includes a base frame, an X-Y gantry, a head unit, a printed circuit board carrier, and a parts feeder. The X-Y gantry is installed on the base frame to be moved in an X-Y axis direction of the head unit. The head unit is installed at the X-Y gantry to mount parts fed by the parts feeder on the printed circuit board while moving. The printed circuit board having the parts mounted thereon is carried to a parts mounting work position by the printed circuit board carrier.
The construction of the surface mounting device for mounting parts on the printed circuit board carried to the parts mounting work position will now be described in detail with reference to the accompanying drawings. FIG. 1 is a perspective view of a conventional surface mounting device. As illustrated therein, the surface mounting device 10 includes a base frame 11, an X-Y gantry 12, first and second head units 13 and 14, a printed circuit board carrier 15, and a parts feeder 16. The base frame 11 is used for supporting the full load of the surface mounting device 10. The X-Y gantry 12 is installed on a plane of the base frame 11.
The X-Y gantry 12 includes an Y-axis stator frame 12a, a plurality of Y-axis permanent magnets 12b, an Y-axis mover 12c, an X-axis stator frame 12d, a plurality of X-axis permanent magnets 12e, and an X-axis mover 12f. The plurality of Y-axis permanent magnets 12b consisting of N and S poles are installed on an inner sidewall of the Y-axis stator frame 12a, and the plurality of X-axis permanent magnets 12e consisting of N and S poles are installed on an inner sidewall of the X-axis stator frame 12d. The Y-axis mover 12c is installed inside the Y-axis stator frame 12a at which the Y-axis permanent magnets 12b are installed, and the X-axis mover 12f is installed inside the X-axis stator frame 12d. 
On a plane of the X-axis mover 12f, the first head unit 13 is installed. When an electric signal is supplied to a plurality of armature coils (not shown) installed at the X-axis mover 12f, the first head unit 13 moves in an X-axis direction by a thrust force generated between the armature coils and the X-axis permanent magnets 12e. To move the first head unit 13 in an Y-axis direction, the X-axis stator frame 12d is moved in the Y-axis direction.
To move the X-axis stator frame 12d in the Y-axis direction, the X-axis stator frame 12d is formed integrally with the Y-axis mover 12c. The Y-axis mover 12c having the X-axis stator frame 12d formed integrally is installed inside the Y-axis stator frame 12a. When an electric signal is supplied to a plurality of armature coils (not shown) installed at the Y-axis mover 12c, a thrust force is generated between the armature coils and the Y-axis permanent magnets 12b. By this thrust force, the Y-axis mover 12c is moved in the Y-axis direction.
As the Y-axis mover 12c moves, the X-axis stator frame 12d formed integrally with the Y-axis mover 12c moves in the Y-axis direction and thusly the first head unit 13 moves in the Y-axis direction. The second head unit 14 moves in the X-Y axis direction in the same way as the first head unit 13. The first head unit 13 and the second head unit 14 moving in the X-Y axis direction mount parts on the printed circuit board carried by the printed circuit board carrier 15.
To mount parts on the printed circuit board using the first head unit 13 and the second head unit 14, firstly, the first head unit 13 and the second head unit 14 suck parts. The parts are mounted at the parts feeder 16 in a tape reel (not shown) state. When the parts are separated from the tape reel mounted at the parts feeder 16, the first head unit 13 and the second head unit 14 suck the parts and then the parts are mounted on the printed circuit board 1. The printed circuit board 1 having the parts mounted will now be described with reference to the accompanying drawings.
As illustrated in FIG. 2, the printed circuit board carrier 15 includes a base frame 15a, first and second guide frames 15b and 15c, a width adjusting screw 15d, a plurality of lifting members 15e, a stopper 15f, a stopper roller 15g, and a width adjusting screw 15h. The first guide frame 15b and the second guide frame 15c are installed at both side of the base frame 15a. The width adjusting screw 15d is installed between the first guide frame 15b and the second guide frame 15c. The width adjusting screw 15h is installed at a position at a predetermined distance from the width adjusting screw 15d. 
The stopper 15f installed at the stopper roller 15g is disposed at one side of the width adjusting screw 15h, and the plurality of lifting members 15e are provided between the width adjusting screw 15d and the width adjusting screw 15h. The printed circuit board carrier 15 carries the printed circuit board 1 to a parts mounting work position (a). When the printed circuit board 1 is carried to the parts mounting work position (a) by the stopper 15f, the position is fixed by the lifting member 15e. Afterwards, the mounting of parts is finished, the printed circuit board 1 is discharged.
As described above, since the conventional surface mounting device having a printed circuit board carrier is constructed in a single structure, it can mount parts carried by a plurality of head units on only one printed circuit board, and thusly the productivity of the mounting work cannot be improved.